As a viscous composition, there are mentioned a cosmetic composition for use for various cosmetics and others; a gel-type composition for use for promotion of viscosity increase or for gelation; and further a spray composition for use for spray nebulization, etc.
Heretofore, for cream-type, gel-type, emulsion-type or liquid-type cosmetic materials, a composition is used wherein a polymer material or the like is mixed with a dispersant medium such as water, alcohol, oil or the like. The polymer material is used for the purpose of imparting shape retention performance (shape retention capability) for maintaining viscosity increase and dispersion stability, and for example, water-soluble cellulose derivatives such as methyl cellulose, carboxymethyl cellulose salt, etc.; synthetic polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, carboxyvinyl polymer, polyethylene glycol, etc.; natural polymer polysaccharides such as quince seed, bee gum, xanthane gum, hyaluronic acid salt, etc. are used. Most of these polymer materials are soluble in water, and are therefore stringy and are not felt good to use, and many of them have poor salt tolerance.
In the background, a cosmetic composition not having the feeling in use specific to water-soluble polymer but excellent in dispersion stability is desired. For the cosmetic composition of the type, for example, a cosmetic composition which includes cellulose particles prepared through hydrolysis and physical grinding of natural cellulose without regeneration (Patent Reference 1) is proposed. This is a composition in which the fat fraction is lowered than in conventional cosmetic compositions and which can attain creamy or emulsion-like properties. However, since it contains coarse grains having a large grain size, the dispersiveness thereof is insufficient to cause a rough feel of the composition.
As a technique of highly dispersing cellulose, a method for producing microfibrillar cellulose by processing an aqueous suspension of pulp with a high-pressure homogenizer to grind it to a microfibril level t is proposed (Patent Reference 2). Since the high-degree dispersion of cellulose to be obtained according to the production method must be processed by the use of an extremely large quantity of energy and the degree of dispersion thereof is insufficient, it is impossible to erase the rough feel specific to the dispersion. Furthermore, the conventional microfibrillated cellulose dispersions are all white and nontransparent, and therefore have a problem in that they could not be applied to cosmetic materials required to be transparent.
To solve the problem, a cosmetic composition that includes cellulose microfibrillated in nanosize is proposed (Patent Reference 3). However, those described in the patent publications are still insufficient for solving the above-mentioned problems, as described below.
On the other hand, as a tackifier and a gelling agent, natural polymer compounds such as Jerangam, carrageenan, agar, xanthan gum, etc.; nonionic water-soluble celluloses such as methyl cellulose, hydroxylmethyl cellulose, etc.; ionic celluloses such as carboxymethyl cellulose, cationized cellulose, etc.; synthetic polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, sodium polyacrylate, carboxyvinyl polymer, polyethylene glycol, etc.; water-swellable clay minerals such as smectite, etc are conventionally used.
However, since the above-mentioned natural polymer compounds are poorly soluble in water, heat treatment of water in the process of producing gel-type compositions is required and consequently have a problem of poor producibility. Additionally, there is another problem that when fragrance or the like is added thereto, a part of the added fragrance or the like may evaporate away. On the other hand, since the above-mentioned nonionic water-soluble celluloses have high solubility in water, heat treatment of water is not necessary. However, for obtaining gel-type compositions, there is a problem in that a large quantity of the water-soluble cellulose must be added. In addition, the above-mentioned synthetic polymers such as sodium polyacrylate, carboxyvinyl polymer and the like are troublesome in that a special attention must be paid thereto so as not to form unmixed-in lumps in dispersing and dissolving them and that they require pH control. It is disclosed that the above-mentioned xanthan gum is stringy and, in use for cosmetics and the like, it causes a sticky feeling (Non-Patent Reference 1). Most of these natural polymer compounds, water-soluble celluloses and synthetic polymers have many problems in point of the range of use and the designability thereof in that their viscosity greatly lowers depending on co-existing salts and they are stringy.
In the situation, a nasal gel using a carboxyvinyl polymer as the gelling agent therein has been proposed, and it is disclosed that the gel has been improved to prevent dripping and has an effect of promoting the absorbability of the pharmaceutical ingredient therein (Patent Reference 4). In addition, it is disclosed that cellulose particles downsized to a few 10 nm have high transparency and can show high performance of thickening, dispersion and emulsion stabilization and structure stabilization even when a small amount thereof is added (Patent Reference 5). However, those described in these patent references are still unsatisfactory for solving the above-mentioned problems, as described below.
In general, spray products are used as products in a broad field of hair-care products, skincare products, aromatic substances, detergents, various coating agents, agricultural chemicals and others. Many spray products are commercialized by charging a liquid composition in a spray apparatus. The properties necessary for spray products are that they can be sprayed by using ordinary spray containers under broad environmental condition (temperature, humidity, etc.); that the sprayed droplets could have a suitable size depending on the intended use and are free from spraying unevenness; and that they are also free from dripping when sprayed onto vertical faces or inclined faces.
Recently, a lot of sprayable gel-type compositions have been proposed (see Patent References 6 to 9). These sprayable gel-type compositions have excellent characteristics in that they are free from a trouble of dripping when they are sprayed on vertical faces or inclined faces.
For example, in Patent Reference 6, a gel-type mist cosmetic product using a clay mineral, smectite is proposed. In Patent Reference 7, a gel-type composition for spray, also using a clay mineral, hectorite is proposed. Since these clay minerals are in the form of extremely small particles, they can swell with water or with any other solvent and disperse thereinto to form a sol/gel. Since the dispersion of the clay mineral has thixotropy, when a pressure (force) on a certain level or more is given, it liquefies, while when released from the pressure (force), it immediately change into gels. Using the property specific to the clay mineral, the above-mentioned composition for spray may be combined with a spray container, to enable spraying the composition without the trouble by dripping.
In Patent Reference 8, an aerosol composition which is for mist-like spraying of an aqueous liquid concentrate having a high viscosity for uniform adhesion with no dripping is proposed. In the aqueous liquid concentrate, a cellulosic thickener and a crosslinked acrylic thickener are used. In case of these thickeners, stringiness is not shown even in a high viscosity and show high-level thixotropy. Therefore they can be excellent gel-type spray compositions.
In Patent Reference 9, a composition for spray agent, which includes cellulose fine particles having a mean degree of polymerization (DP) of 100 or less, a fraction of cellulose I-type crystal component of 0.1 or less, a fraction of cellulose II-type crystal component of 0.4 or less and a mean particle size of 2 μm or less, and a liquid dispersion medium, wherein the cellulose concentration is from 0.1 to 5.0% by weight and on the viscosity-shear stress curve of the composition, which is measured with a cone-plate type rotatory viscometer at 25° C. in a shear rate region including at least from 1×10−3 S−1 to 1×102 S−1, the maximum value of the viscosity (ηmax) is ηmax≧1×103 mPa·s. The cellulose fine particles used in the spray composition can be obtained through acid hydrolysis of natural cellulose or regenerated cellulose. The spray composition including the above-mentioned cellulose particles is transparent in an aqueous medium and have excellent properties in that its mother droplets can well fix on the sprayed surface with little spraying unevenness and the sprayed mother droplets are free from a trouble of dripping on vertical faces and inclined faces. However, those described in these patent publications are still unsatisfactory for solving the above-mentioned problems, as described below.